Impact tool



March 5, 1957 D. B. GRAVES ET AL 2,783,570

IMPACT TOOL.

Filed Aug. 16, 1955 .IrEr-ars .ENT s III United States Patent O llVIPACT TOOL Delbert B. Graves and Elmer Schlichting, Nora, lll.,

assignors of one-half `to -William Neiman, Free- Ilwrtlu.

Application August 16, 1955,' Serial No. 4528,722

=7 Claims. .(Cl. 81-f52g3,5)

This invention relates to `impact tools and more particularly pertains -to -a portableimpact tool.

An vimportant object of this invention is to providea portable impact tool-which is adapted A'to'be SURPOrted and operated -with one hand.

,Another object ofthis'inventionis"tozprovide a portable Vimpacttool which may 'be easily positioned and operated in confined spaces.

A further object of this invention ,is to provlide a portable impact tool having anovel construction for releasably retaining the inertia element'inits cocked position arranged to permit releasing of the inertia element with a minimum of eiort.

Still another vobject ot'this invention is to 3provide a portable impact tool -which is particularly adapted `for inserting and removing expansion plugs.

These, together with various ancillary objects and advantages of this invention will be more readilyappreciated as the same becomes better understood fby reference ,to the following detailed description when-taken in Connection with the accompanying drawings wherein:

Figure l is a longitudinal `sectional view through the impact tool shown in kposition to apply an expansion Plug;

Fig. 2 is an end elevational view of the impact tool; and

Fig. 3 is a fragmentary sectional view,'taken on the plane 3 3 of Fig. 1.

The impact tool, designated generally kby the numeral is particularly adapted for inserting and removing the dome-shaped expansion plugs 1-1 commonly used to seal openings in castings such as -the core opening 12 in the cylinder block 13 of an internal combustion engine. Such core openings are provided to facilitate vcasting of the cylinder block and in order to seal these openings, the latter are counterbored as indicated at 14 and the domeshaped expansion plug disposed therein. The expansion plug is sealed to the casting by hammering on the central portion thereof to change the curvature and thereby radially expand the plug into a tight it with the casting.

The expansion plugs 11 frequently work loose after a period of time and develop la Vleak therearound. 'It is then necessary to remove the expansion plugs and insert new plugs in their place. Because of the numerous parts located under the hood of an automobile, there is frequently insuilicient .space around .the cylinder block to permit manipulation of a hammer for inserting and removing these plugs.

The impact tool 10 is arranged so vas to 'be supported and operated with one hand to permit manipulation of the impact tool inthe conti-ned spaces under the hood. More particularly, the impact tool includes a heavy cylindrical body 16 having an axial Vbore 1'7 extending therethrough. The thickness of the walls of the `body are made sucient to provide the-necessary weight in the body to absorb the reaction `of the inertia element, to be described more fully hereinafter. One 'lface of the body `16 is ,chamferedas indicate'd'at'118. and isv formed with an annular groove '19 inthe end-thereof=to provide a reduced diameter nose portion '21 having a .diameterto be yloosely Yinserted in ythe counterbore 14 to center the impact tool thereon.

A plunger designated generally by'the numeral22 is slidably disposed in the bore k17 and, `as best shown in Fig. l, includes an enlarged intermediate 'portion 23 having a slidingtin thebore andareduceddiameter nose portion 24 extending'from one end thereo'fLand terminating in a striking `r`face 25. A reduced diameter guide portion 26 extends axially jfromthe otherend of the intermediate portion Y23 and aheavy compression spring 27 ,is disposed around the guidetportion within'the'bore. One end `of the spring 27 engages the intermediatevportion o n the plunger and the other end engages an abutment 28 which is vthrea'detlly received in fthe linternally threaded end 2,9 of Vthe bore. lThe abutment is thus threadedly adjustable v longitudinally of the bore to vary the compression ofthe s pring'27V and, conveniently, the air 'hole 31 provided "inthe abutment is formed of a polygonal cross-section `for the reception of a suitable tool to facilitate -adjustment of the. abutment. v

`A beveled shoulder 33is `formed at the vjuncture of the intermediate portion 23 `and :the reduced zdiameter nose portion 24, which shoulder .extends downwardly and inwardly from the intermediate `portion. A'latchmember 34 vis mounted formovement `into andout of .engagement-with Athe :shoulder to releasablyretain the plunger 22 in a cocked position. tln accordance with the present invention, the latch member is inthe form of an elongated barhaving apolygonalcross-section .slida'bly disposed in la complementary opening "35. inithe'body `1.6 and arranged to extend substantially radially of the body, intermediate the ends thereof. "The inner end of the latch member 34 i s beveled as indicated at'136 complementary to the beveled shoulder '33 and is arranged ,to extend inwardly into the bore17 in the `body into thepath of movement of the shoulder. The latch member34 is yieldably urged inwardly ofthe body, 'as by .the leaf spring 38 which is anchored by a fastener 39 onv the outer side of the body and engages the Ynotch 41 on Athe outer end .of the latch member. The cam surface 36- onthe inner Aend of the latch member andthe beveledshoulder 33 are-arranged so that the latch member 34 will'be cam operated to its release position by the plunger I22 under the bias of spring 27. Provision is made 'for positively -locking the latch member against movement'to its release position and for this purpose there is iprovided a latch lever 43 which -is engageable ywith the outer end of the llatch member 34. The latch lever 43 is mounted between spaced ears 44 of Vafbracket5j2 having. anges 45 welded or otherwise rigidly secured -to the 'outerrperiphery of the body 16. The lever 43 4ismounted for pivotal movement on Aa pin 46 journaled in the ears 44, which pin is preferably disposed inthe path of movement of the latch member 34 -and --extends'aperpendicular -to' .the longitudinal axis ofthe latch member. A nose portion 47 is formed on the lever for engagement with'the latch member and preferably Vis formed-with-a surface 48 kfor vengagement with the Vend of the'latchmember, which surface is disposed substantially concentric of the pivot pin y46. The operating lever 43 includes Aa handle portion '49 which preferably extends alongside thebody y'1-6 to permit manipulationby `one `of the digits 'of the hand-used to gripV the impact tool. A leaf spring '-51 is also atlixed vto `the body by the fastener 139 and engages vthedever 43 YLto move the .latter in -adirectionl yto `cause 'theA nose portion 47 of the lever to abut the latch member34. .The web of the lever mounting Vbracket'SZ extends between the ears 44 and iis lengageable vwith 'the "handle ,portion of the operating lever to provide a stop for limiting move-A ment of the lever by the spring to a preselected position in which the surface 48 on the end of the nose portion of the lever engages the outer-end of the latch member.

AAn annular internal groove S4 is `formed in the body 16, adjacent the nose portion thereof anda split ring 55 is disposed in this groove for engagement with the shoulder 33 on the plunger to limit movement of the latter outwardly of the bore.

In use of the impact tool, the plunger 22 is cocked by positioning a block (notshown) against the striking face 2S andthen interposng the block and impact tool in avise or the like with the block against one jaw of the device and the remote end of the impact tool against the other jaw.V As the jaws are moved together, the plunger 22 is moved inwardly against the bias of spring 27 and, when the shoulder 33 moves inwardly beyond the latch member 34, the latter is moved by the leaf spring 38 into a position underlying the shoulder. Simultaneously, the latch lever 43 is moved by spring 51 in a counterclockwise direction as viewed in Fig. l to move the end 48 of the nose portion 47 against the outer end of the latch member 34. The latch lever 43 then positively retains the latch member in its vlatching position until the lever is manually operated to release the latch member.

As previously described, the body 16 is dimensioned so as to permit gripping the latter with `one hand and the weight of the body is made sufficient to minimize recoil. The body 16, when gripped with one hand, may be manipulated in confined spaces such as under the automobile hood, to position the nose portion 19 of the body in the counterbore 14. The plunger is then released by moving the lever 43 in a clockwise direction to move the nose portion 48 away from the outer end of the latch member. The plunger 22, acting through the beveled shoulder 33 against the beveled surface 36 on the inner end of the latch member, cam operates the latter out of the path of movement of the plunger whereby the latter moves downwardly in the bore 17. The striking face 25 on the plunger is made somewhat smaller than the bore 17 in the body, and smaller than the hole 12 being plugged, so as to engage the central portion of the domeshaped plug 11 and expand the latter. As is apparent, the device may also be used for removing the loosened expansion plugs by repeatedly using the impact tool to strike the expansion plug and produce an opposite concavity in the plug which diametrically contracts the latter and permits easy removal.

Since the end 48 of the nose portion on the lever 43 is disposed concentric with the pivot pin 46 of the lever, it is apparent that no appreciable movement of the latch member 34 occurs until the nose portion has moved out of engagement with the latch member. Consequently, little effort is required to release the plunger 22, notwithstanding the relatively high pressure which is exerted upon the plunger by the spring 27.

We claim:

l. An impact tool comprising a heavy cylindrical body having a bore extending inwardly from one end thereof, a plunger slidably disposed in said bore and having a striking face at one end, a spring disposed in said bore for urging the plunger in a direction to move the striking face outwardly of said bore, means dening a stop on said plunger, a latch member mounted on said body for movement in a direction transverse to the direction of movement of said plunger into engagement with said stop to retain the plunger in a preselected position in said bore, cam means on said latch member and stop operable under the bias of said spring on said plunger for urging the latch member out of engagement with said stop, and a latch lever mounted on said body and engageable with said latch member for releasably retaining said member in engagement with said stop.

2. An impact tool comprising Va heavy cylindrical body having a bore extending inwardly from one end thereof, aplunger'slidably disposed in said bore and having a striking face at one end, a spring disposed in said bore for urging the plunger in a direction to move the striking face outwardly of said bore, means defining a stop on said plunger, a latch member slidably mounted on said body for movement in a direction transverse to the direction of movement of said plunger into engagement with said stop to retain the plunger in a preselected position in said bore, the inner end of said latch member and said stop having cam surfaces formed thereon and operable under the bias of said spring acting on said plunger for urging the latch member out of engagement with said stop, a latch lever mounted on said body and cngageable with said latch member for releasably retaining said member in engagement with said stop.

3. An impact tool comprising a heavy cylindrical body having a bore extending inwardly from one end thereof, a plunger slidably disposed in said bore and having a striking face at one end, a spring disposed in said bore for urging the plunger in a direction to move the striking face outwardly of said bore, means `dening a stop on said plunger, a latch member slidably mounted on said body for movement in a direction transverse to the direction of movement of said plunger into engagement with said stop to retain the plunger in a preselected position in said bore, the inner end of said latch member and said stop having cam surfaces formed thereon and operable under the bias of said spring acting on said plunger for'urging the latch member out of engagement with said stop, a latch lever pivotally mounted on said body and having a nose portion engageable with the outer end of said latch member for releasably retaining the latter against movement by said cam means out of the path of said stop, said latch lever being movable to disengage the nose portion thereof from the outer end of said latch member whereby said member is moved by said cam means out of the path of said stop and said plunger moves in the bore under the bias of said spring.

4. The combination of claim 3 including a rst spring means engageable with said latch member for yieldably urging the member into engagement with said stop,'and a second spring means for yieldably urging said latch lever in a direction to move the nose portion thereof into engagement with the outer end of thelatch lever.

5. An impact tool for use in conined spaces comprising a heavy cylindrical body dimensioned to be gripped in one hand, said body having a bore extending therethrough, a plunger having an enlarged intermediate portion slidably disposed in said-bore, a reduced diameter nose portion extending from one' end of said intermediate portion and terminating in av striking face smaller than said bore, a beveled shoulder at the juncture of said intermediate portion and said nose portion, a reduced diameter guide portion extending from the other end of said intermediate portion, a spring disposed in said bore around the guide portion and engageable with said other end of the intermediate portion of the plunger, an abutment threaded into said bore and engaging the other` end of said spring for adjusting the pressure on said-spring, said body having a radial passage extending therethrough intermediate its ends, a latch member slidably disposed in said passage and having a beveled inner end complementary to said shoulder and engageable with the latter, said beveled shoulder and the beveled inner end of said latch member being shaped so that the spring acting on said plunger is operable to cam actuate said latch member out of engagement with said shoulder, and a latch member pivotally mounted on said body and having a nose portion engageable with'the outer end of said latch member for releasably retaining said member in engagement with said shoulder.

6. The combination of claim 5 wherein the pivot axis ofsaid lever overlies the outer end of said latch meanber, said lever having an operating handle extending alongside said body and adapted for manipulation by a References Cited in the tile of this patent digit of the hand used to grip said body. NIT P 453,203 Italy NOV. 23, 1949 636,815 Great Britain May 10, 1950 

